Helping the State visualize what’s at stake as oceans acidify

A summary of the latest research on ocean acidification (OA) impacts to important species and ecosystems in California, from crab to squid, rockfish to urchins. This tool provides a tangible illustration of our current knowledge to support decision-makers in prioritizing efforts and resources to address OA impacts.

Ocean Science Trust, working closely with scientists at UC Davis Bodega Marine Lab, the Ocean Protection Council (OPC) and other partners, undertook this synthesis to help identify data gaps and prioritize where to allocate resources to further increase understanding of OA impacts to California fishery resources.

Ocean acidification is a complex issue that has the potential to alter marine food webs and ecosystems in California, with direct and indirect impacts to valuable marine fisheries and the aquaculture industry. Currently, state agencies working to understand the risks OA poses to coastal species, ecosystems, and human communities – an essential step to helping those at risk prepare for what’s at stake as coastal oceans continue to acidify.

VISUALIZING IMPACTS OF OA TO LIVING MARINE RESOURCES IN CALIFORNIA

As a first step towards illuminating potential natural resource management solutions, Ocean Science Trust worked closely with scientists at UC Davis Bodega Marine Lab, the Ocean Protection Council and other partners to demonstrate the potential impacts of OA on important species and ecosystems in California. We undertook a synthesis of current scientific understanding and developed communications material for use by resources managers. The species included in the synthesis represent a diverse subset of species considered as ocean climate indicators, commercially, recreationally, and/or ecologically important. This list was selected by the project team and vetted and augmented by OPC, CDFW, and aquaculture representatives.

WORKSHOP: DEFINING OCEAN ACIDIFICATION HOTSPOTS IN CALIFORNIA

Building on this assessment, Ocean Science Trust hosted a workshop in November 2018, to help managers and decision-makers incorporate OA impacts information into relevant management decisions, prioritize efforts to address these impacts, and determine where to allocate resources to further increase understanding. This workshop brought together managers, policy makers, and scientists to better understand the concept of OA hotspots, ensure it is usable by state decision-makers, and identify key gaps in data and information that inhibit action.

Findings from this work may also:

Help identify research and data gaps to understanding OA impacts to California’s fishery resources

Inform species selection for a modeling exercise to identify species vulnerability thresholds

Provide the groundwork for a quantitative OA or climate vulnerability assessment for California or the West Coast

A melting iceberg floats along a fjord leading away from the edge of the Greenland ice sheet near Nuuk, Greenland, in 2011. By this century’s end, if emissions continue at their current pace, humans will have warmed the ocean about 20 percent as much as during the Permian extinction event, newly published research says. (Brennan Linsley / The Associated Press)

If humans continue to pump greenhouse gases at our current rate, “we have no reason to think it wouldn’t cause a similar type of extinction,” said Curtis Deutsch, a UW professor and author of the research.

More than two-thirds of life on earth died off some 252 million years ago, in the largest mass extinction event in Earth’s history.

Researchers have long suspected that volcanic eruptions triggered “the Great Dying,” as the end of the Permian geologic period is sometimes called, but exactly how so many creatures died has been something of a mystery.

Now scientists at the University of Washington and Stanford believe their models reveal how so many animals were killed, and they see frightening parallels in the path our planet is on today.

Models of the effects of volcanic greenhouse-gas releases showed the earth warming dramatically and oxygen disappearing from its oceans, leaving many marine animals unable to breathe, according to a study published Thursday in the peer-reviewed journal Science. By the time temperatures peaked, about 80 percent of the oceans’ oxygen, on average, had been depleted. Most marine animals went extinct.

The researchers tested the model’s results against fossil-record patterns from the time of the extinction and found they correlated closely. Although other factors, like ocean acidification, might have contributed some to the Permian extinction, warming and oxygen loss account for the pattern of the dying, according to the research.

By this century’s end, if emissions continue at their current pace, humans will have warmed the ocean about 20 percent as much as during the extinction event, the researchers say. By 2300, that figure could be as high as 50 percent.

“The ultimate, driving change that led to the mass extinction is the same driving change that humans are doing today, which is injecting greenhouse gases into the atmosphere,” said Justin Penn, a UW doctoral student in oceanography and the study’s lead author.

Curtis Deutsch, a UW associate professor of oceanography and an author of the research, said if society continues to pump greenhouse gases at our current rate, “we have no reason to think it wouldn’t cause a similar type of extinction.”

Massive eruptions

The earth 252 million years ago was a much different place. The continents as we know them today were still mostly one landmass, named Pangea, which looks like a chunky letter “C” on a map.

The climate, however, resembled Earth’s now, and researchers believe animals would have adapted many traits, like metabolism, that were similar to creatures today. Nearly every part of the Permian Ocean, before the extinction, was filled with sea life.

“Less than 1 percent of the Permian Ocean was a dead zone — quite similar to today’s ocean,” Deutsch said.

The series of volcanic events in Siberia that many scientists believe set off the mass extinction “makes super volcanoes look like the head of a pin,” said Seth Burgess, a geologist and volcanologist with the United States Geological Survey.

“We’re talking about enough lava erupted onto the surface and intruded into the crust to cover the area of the United States that if you looked at the U.S. from above was maybe a kilometer deep in lava,” he said.

Burgess, who has researched the Siberian Traps volcanic events but did not work on the new Science paper, said scientists believe magma rising from the earth released some extinction-causing greenhouse gases.

In addition, sills of magma still inside the earth heated massive deposits of coal, peat and carbonate minerals, among others, which vented even more carbon and methane into the atmosphere.

“That’s how you drive the Permian mass extinction, by intruding massive volumes of magma into a basin rich in carbon-bearing sediments,” he said.

The UW and Stanford research “takes the next step in figuring out why things died at the end of the Permian,” Burgess said. “It couples what we think was happening in the climate with the fossil record, and it does it elegantly.”

Animals couldn’t breathe

It took a supercomputer more than six months to simulate all the changes the volcanic eruptions are suspected of causing during the Permian period. The computer models go into remarkable detail — simulating things like clouds, ocean currents and marine plant life — in describing what temperatures and conditions were like on Earth.

The researchers knew that surface temperatures rose about 10 degrees Celsius in the tropics because of previous scientific analysis of the fossilized teeth of eel-like creatures called conodonts.

To run their model, researchers pumped volcanic greenhouse gases into their simulation to match temperature conditions at the end of the Permian period.

As temperatures climbed toward the 10-degree mark, the model’s oceans became depleted of oxygen, a trend scientists are evaluating in today’s oceans, too.

To measure how rising temperatures and less oxygen would affect animal species of the Permian period, the researchers used 61 modern creatures — crustaceans, fish, shellfish, corals and sharks. The researchers believe these animals would have similar temperature and oxygen sensitivities to Permian species because the animals adapted to live in similar climates.

Warming’s effects were twofold on the creatures, the researchers found. In warmer waters, animals need more oxygen to perform bodily functions. But warm waters can’t contain as much dissolved oxygen, which means less was available to them.

In other words, as animals’ bodies demanded more oxygen, the ocean’s supply dropped.

In their model, the researchers were able to quantify the loss of habitat as species faced increasingly challenging ocean conditions. Surface-temperature rise and oxygen loss were more substantial in areas farther from the equator. Extinction rates also increased at higher latitudes.

Animals in the tropics were already accustomed to warmer temperatures and lower oxygen levels before the volcanic eruptions shifted the climate, according to the research. As the world warmed, they could move along with their habitat.

Marine creatures that favored cold waters and high oxygen levels fared worse: They had nowhere to go.

“The high latitudes where it’s cold and oxygen is high — if you’re an organism that needs those kind of conditions to survive, those conditions completely disappear from Earth,” Deutsch said.

In modern oceans, warming and oxygen loss have also been more pronounced near the poles, researchers said, drawing another analogue between the shift in climate some 252 million years ago and what’s happening today.

“The study tells us what’s at the end of the road if we let climate [change] keep going. The further we go, the more species we’re likely to lose,” Deutsch said. “That’s frightening. The loss of species is irreversible.”

Arctic Report Card: Update for 2018 – Tracking recent environmental changes, with 14 essays prepared by an international team of 81 scientists from 12 different countries and an independent peer-review organized by the Arctic Monitoring and Assessment Programme of the Arctic Council. See https://www.arctic.noaa.gov/Report-Card

Those are two takeaways from the 2018 Arctic Report Card, which was released Tuesday at the American Geophysical Union conference in Washington, D.C. The 13th year of this peer-reviewed report card features 14 essays by 81 scientists from 12 countries.

Few places will feel the blight of climate change as hard as the Arctic. Our upper pole is warming faster than any other region on Earth, a trend that may be tied to erratic weather patterns across the northern hemisphere.

For the first time, the report card includes a warning about red tide and harmful algal blooms, which are expanding due to a lack of ice and warming ocean temperatures. Toxins from these micro-organisms are threatening marine wildlife and coastal fisheries, imperilling communities that depend on these species.

This year will also enter the record books as the second warmest for the Arctic since 1900, said Emily Osborne of the NOAA Arctic Research Program.

“The only warmer year occured in 2016,” Obsorne said, adding that Arctic air temperatures for the past five years have exceeded all records since the beginning of the 20th century. “The Arctic is experiencing the most unprecedented transition in history.”

Here are three things you need to know about the Arctic Report Card.

Red tide

When you hear about harmful algal blooms, the mind typically wanders to Florida, where thick scums of blue-green algae and clouds of red tide have floated in the state’s warm waters for more than a year.

Due to a warming Arctic Ocean, at least five families of these harmful micro-organisms are now present in other northern waters, like the Chukchi and Bering seas.

“The vast majority of the Arctic ocean has experienced clear long- term trends of warming,” said Karen E. Frey, a geographer and biogeochemist at Clark University in Worcester, Massachusetts. Microscopic creatures are thriving in these waters. Near St. Lawrence Island, for instance, west of the Alaska mainland, aquatic biomass in 2018 increased between 275 and 500 percent relative to the average over the last 14 years.

These harmful algal blooms produce a range of toxins, which can poison other plankton, fish, shellfish, birds and humans. One study of stranded marine mammals — like whales and seals — found the algal toxin domoic acid in all species tested.

Mounting microplastics

This explosion in tiny creatures has been paralleled by the rapid rise of microplastics in the Arctic Ocean. The Arctic Basin contains more microplastic than all other ocean basins in the world, according to a study published in June and cited in the report card, with the highest concentrations stuck in the Beaufort Sea.

These microplastics have made multiple intrusions into the food web, being found in everything from polar cod and seafloor-hugging invertebrates to Arctic birds. The plastic waste has also been found buried in sea ice, which scientists are using to study its abundance.

The major sources of these microplastics remain unclear. They could be floating to the Arctic from other oceans, but some contribution is due to waste like fishing nets and other gear from shipping activities, which have increased substantially since 2009.

The greening of the Arctic continues to gradually grow. Vegetation has expanded overall in the Arctic for the last 36 years, according to the new report card. As shrubs and grasses expand, some species of birds and mammals are thriving. Caribou and wild reindeer, both herbivores, are not part of this lucky class.

Arctic caribou in North America and Greenland and reindeer in Russia and Norway have declined 56 percent over the last two decades, with their populations dropping from 4.7 million to 2.1 million. Why?

Increased drought and longer spans of hotter weather are causing outbreaks of infectious bacteria and parasites, said Howard Epstein, an ecologist at the University of Virginia. The caribou and reindeer populations are also declining due to a boon in predators and because extreme weather events are occasionally triggering droughts.

Wacky weather and the eviction of older ice

The Arctic pattern most pertinent to our daily lives, here in North America, revolves around warmth.

Warm air temperatures, which are increasing at twice the rate of the remaining world, continue to disrupt the polar jet stream, making it sluggish and unusually wavy. A surge of warm Arctic weather in 2017 coincided with severe winter storms in the eastern United States at the beginning of 2018 and a cold snap in Europe in March. Osborne said the jury is still out on the strength of the connection between Arctic warming and wacky weather in the mid-latitudes, but at the moment, the correlation is solid.

This atmospheric warming also drove declines in Arctic snow cover and caused melting of the Greenland ice sheet. But the biggest loser, in terms of frozen water, is Arctic sea ice. Older packs of Arctic sea ice, which used to be impervious to the annual melting cycle, are thinner and covering less area than they have in the past. The oldest ice has declined by 95 percent in the last 33 years.

“During two weeks in February, which is typically the height of ice growth, the Bering Sea lost a piece of ice the size of Idaho,” said Donald Perovich, a sea ice geophysicist at Dartmouth College in New Hampshire. March witnessed the second lowest sea ice extent in 39 years.

Perovich said this loss is being felt hardest by coastal communities, which used to be buffered by the sea ice. The loss is also exposing communities to massive storm surge and disappearing shorelines. It is also depriving coastal residents of a safe route for hunting and travel.

Quickest way to reverse declining salmon stocks is to introduce a harvest: Pacific Balance Pinnipeds Society

Greg Rasmussen · CBC News · Posted: Dec 01, 2018 1:00 AM PT

For the first time in decades, a small-scale seal hunt is taking place on Canada’s West Coast — all in the hopes that it leads to the establishment of a commercial industry to help control booming seal and sea lion populations and protect the region’s fish stocks.

In early November, a group called the Pacific Balance Pinnipeds Society (PBPS) started using First Nations hunting rights as part of a plan to harvest 30 seals. The society plans to test the meat and blubber to see if it’s fit for human consumption and other uses.

“We can look at opening up harvesting and starting a new industry,” said Tom Sewid, the society’s director and a commercial fisherman. “Since the [West Coast] seal cull ended in the 1970s, the population has exploded.”

Sewid, who is a member of the Kwakwaka’wakw First Nation, points out that Indigenous people have hunted the animals for thousands of years. Recent decades with little or no hunting have been an anomaly, he said, pointing to research that shows seal numbers are even higher now than in the 1800s.

Out go the nets, in come the sea lions

What’s become an ongoing battle between humans and sea lions played out on a recent nighttime fishing expedition, when Sewid and a crew of commercial fishermen set out in a 24-metre seine boat to fish for herring off the coast of Parksville, B.C.

The crew’s goal was to catch about 100 tonnes of herring, which rise to the surface to feed after dark. But the faint barking of sea lions was soon heard over the thrum of the boat’s diesel engine.

“All them sea lions out there are all happy — [they’re] all yelling, ‘Yahoo, it’s dinner time!'” Sewid said.

Once the crew spotted the herring, they let out hundreds of metres of net, while a smaller boat helped to circle it around the huge mass of fish. The crew then closed the bottom of the net, capturing the herring.

But the catch also provided some uninvited visitors with a captive dinner: Dozens of sea lions jumped over the floats holding up the net and started to gorge.

“These guys, it’s just a buffet for them,” said Sewid, as the bodies of the sea lions glistened in the boat’s floodlights. “Just like pigs at a trough.”

Sewid said the sea lions have learned there’s an easy meal to be had whenever they see or hear the fishing boats.

“They’re not afraid of us. They’ve habituated themselves to seeing that humans and fishing equates easy access to food, which is not right,” he said. “The animal kingdom is not supposed to be like that.”

Restarting a banned hunt

The hunting of seals and sea lions — which are collectively known as pinnipeds — has been banned on the West Coast for more than 40 years. It’s one reason their numbers have exploded along the entire Pacific coastline of North America.

According to one study, the harbour seal population in the Salish Sea is estimated at 80,000 today, up from 8,600 in 1975. The study also says seals and sea lions now eat six times as many chinook salmon as are caught in the region’s commercial and sports fisheries combined.

That adds up to millions of tonnes of commercially valuable fish.

Sewid’s group is proposing to cull current populations of harbour seals and sea lions by half, which would see thousands of the animals killed each year.

Tom Sewid is leading the effort to secure what he calls a sustainable harvest of seals and sea lions along the B.C. coast. (Greg Rasmussen/CBC)

The society’s small-scale “test” harvest is taking place between B.C.’s southern Gulf Islands and as far north as Campbell River, on Vancouver Island. It’s being carried out under the provisions of the Aboriginal Fisheries Strategy, which gives some First Nations harvesting and management rights for food and ceremonial purposes.

Testing the meat to see if it’s safe for human consumption is a first step in a plan to eventually gain permission for what the PBPS envisions as a sustainable, humane commercial hunt, which would largely be carried out by coastal First Nations.

“All the meat that’s in there, you’re looking at the high-end restaurants [that would sell it],” Sewid said. “The hides can also be used.”

Seal blubber is particularly valuable, he said, because it can be rendered down into an oil that’s in demand because of its high Omega-3 fatty acid content.

One of the biggest hurdles facing the group is convincing the federal Department of Fisheries and Oceans to open a commercial hunt on the West Coast.

The seal hunt that takes place in the Atlantic and Arctic is controversial, and has long been subject to protests and fierce opposition from animal rights groups. The group expects a West Coast harvest to also face fierce confrontations.

Canadian Inuit have been waging a counter-campaign, highlighting the importance of the animal and the longstanding tradition of their hunt.

Most Canadian seal products are also banned in Europe and a handful of other countries, but the society says demand is strong in Asia.

Supporters and opponents

The PBPS does have a growing list of supporters, including 110 First Nations groups, a number of commercial fishing organizations, and some sectors of B.C.’s economically important sport fishing sector.

However, one key player, the Sport Fishing Institute of B.C., opposes a large commercial hunt, fearing it would generate public outrage and might not achieve the goal of enhancing fish stocks.

The institute’s director, Martin Paish, says the group sees some value in targeting some seals and other fish predators at specific times of year in a number of key river systems; he believes a limited hunt would help protect salmon stocks and boost the billion-dollar-a-year B.C. sport fishing industry.

“Our goal is to use predator control in a careful manner to improve chinook [salmon] production where it is needed,” said Paish.

Carl Walters is a fish biologist and UBC professor who supports cutting B.C.’s population of seals and sea lions by half. (Nic Amaya/CBC)

Fisheries scientist Carl Walters, a professor emeritus with UBC, believes culling the regions sea lions and seals could dramatically boost salmon stocks. He points to numerous studies showing how pinniped populations have been increasing, while salmon numbers have been plummeting.

“They’re killing a really high percentage of the small salmon shortly after they go into the ocean, about half of the coho smolts and a third of the chinooks,” he said.

Advocates of a hunt are also pitching it as a way to help B.C.’s endangered southern resident killer whales, which feed mainly on salmon.

“The thing that would benefit southern resident killer whales is to see improved survival of small chinook salmon — and I think the only way we can achieve that is by reducing seal numbers,” Walters said.

Peter Ross, from the Coastal Ocean Research Institute, says there would be little benefit to salmon from a seal and sea lion cull. (Nic Amaya/CBC)

Others disagree, including Peter Ross, the vice-president of research and executive director of the Coastal Ocean Research Institute.

“Killing of seals and sea lions is not going to have any positive impact for any salmon populations in coastal British Columbia,” he said.

While a few localized populations of salmon might benefit from a cull, Ross said climate change, habitat destruction and overfishing are all bigger factors in the overall decline of stocks.

Other subspecies of orcas, however, feed mainly on seals, so a hunt would reduce their access to prey.

Back on the boat, Sewid concedes a hunt would be controversial — but he firmly believes it’s necessary.

“All the indicators are there,” he said. “It’s time to get the balance back.”

The fishing crew from the Western Investor are shown harvesting herring in November. But they say they are being hampered by dozens of sea lions in their nets almost every night. (Nic Amaya/CBC)

In cooperation with the California Department of Fish and Wildlife and Southwest Fisheries Science Center, CWPA is developing sampling methods to assess sardine and anchovy in nearshore waters not surveyed in NOAA acoustic trawl surveys. Both sardine and anchovy are abundant in California’s coastal waters inshore of current NOAA acoustic trawl surveys; in fact, approximately 70 percent of California coastal pelagic species landings are harvested in waters not surveyed in federal stock assessments. The sharp decline reported for both sardine and anchovy in recent years is belied by our nearshore surveys, and fishermen’s observations, that find increasing populations of both species. Accurate biomass estimates and stock assessments for CPS will benefit sustainable harvest policies, fishermen and seafood processors who produce these species, as well as our fishing communities and seafood consumers.

Our aerial survey samples CPS schools using aerial spotter pilots with plane and aerial camera system to fly transects near shore and photo-document schools, coupled with qualified purse seine vessels chartered to capture a subset of the schools identified while the pilot photographs the “point sets.”

SAN DIEGO (NEWS 8) – Scientists in La Jolla are using cutting-edge technology to track schools of fish off the west coast.

They’re using Saildrone vessels equipped with sonar to monitor the health of the ocean and fish populations.

It may look like a sailboat but it’s actually a drone, hence the name Saildrone.

Five of the unmanned vessels recently completed a six-month mission to track fish populations from Vancouver to San Diego.

“It works just like a sailboat and it can sail or tack in a specific corridor. We use the solar panels that you see onboard to power the sophisticated sensor suite that’s inside,” said Nora Cohen, a spokesperson for Saildrone, a private company based in Alameda, California.

The Saildrone has a satellite connection that allows scientists to control it using a smartphone app.

It can stay at sea for up to 12 months. The only reason to bring it back to land is so scientists can download the data.

“At the end of the mission we bring the Saildrone back to shore and we transmit the entire, full-resolution data to the scientists for analysis,” said Cohen.

On the most recent mission, the Saildrones teamed up with a San Diego based, NOAA research ship: the 200-foot Reuben Lasker.

“You can see the draft of a Saildrone is quite small, our draft on (the Reuben Lasker) is 30 feet, so we can’t go nearly as close to shore as the Saildrone might be able to,” said Emily Rose, a NOAA Corps lieutenant command onboard the Reuben Lasker.

The five drones and the NOAA research ship were all equipped with sonar that locates large schools of fish underwater.

“That sound bounces off of the fish schools and the intensity of those echoes tells how many fish are in the ocean,” said NOAA researcher Juan Zwolinski.

The scientists use NOAA’s 500,000 gallon Ocean Technology Development Tank to make sure the sonar equipment is calibrated using underwater metal targets and live fish.

“With this data we estimate the abundance of fish stocks. That’s all the anchovies, sardines, mackerel, and so on. We assess them year by year and over time we can track their populations and predict what they will be into the future,” said Zwolinski.

NOAA verifies the sonar images captured at sea by lowering nets and actually catching sample fish from the schools detected.

“Understanding the population and where the fish are really helps us understand what’s going on with the fish stocks, and helps us make educated and informed decisions concerning closing a fishery or restricting fishing until the fishery rebounds,” said NOAA Corps Lt. Cmdr. Rose.

This article stated: The National Oceanic and Atmospheric Administration announced in January that California sea lions had reached carrying capacity—the number of individuals their environment can sustainably support—in 2008.

The expected symptoms of a population of mammals at carrying capacity include reduced reproductive output, decreased growth and survival of young animals, delayed sexual maturity, increases in disease or parasites and decreased size and survival of adults. There have beenrecent increases in California sea lion pup mortality and reduced pup growth rates, as well as increased incidence of leptospirosis observed in central California and Oregon, leading to the suggestion that the population is approaching carrying capacity (McClatchieet al. 2016).

Leptospirosis afflicts sea lions on a semi-regular cycle, but warming waters and migrating fish could make the marine mammals more susceptible

Princepajaro, a male California sea lion, swims in a pool during treatment for leptospirosis at The Marine Mammal Center in Sausalito, CA. When a leptospirosis outbreak occurs, the Center’s scientists study the disease to learn more about what causes an outbreak and how we can improve treatment for infected animals. (Bill Hunnewell / The Marine Mammal Center)

Shawn Johnson knew it was coming.

“Last fall, we saw a few cases,” he said. “And that was a warning signal, so we were prepared—well, we weren’t prepared for this level of an outbreak.”

Over the past month, Johnson, director of veterinary science at the Marine Mammal Center, just north of San Francisco, and his team have been getting an average of five sick California sea lions a day. The animals have leptospirosis, a bacterial infection that affects their kidneys, causing fatigue, abdominal pain and, more often than not, death.

As of October 16, Johnson’s team had seen 220 sea lions with the disease, which made it the center’s second largest outbreak. Since then, the center reported 29 more sea lions have been rescued and 10 of those died due to leptospirosis. More than a dozen animals are still awaiting diagnosis. The number of cases has started to slow, but if historical trends hold up, Johnson expects this outbreak to eventually surpass 2004’s record of 304 cases of sea lion leptospirosis.

The Marine Mammal Center in Sausalito, CA, is responding to an outbreak of a potentially fatal bacterial infection called leptospirosis in California sea lions. The pictured sea lion, Glazer, is seen curled up with his flippers folded tightly over his abdomen prior to his rescue by trained Center responders in Monterey. The posture exhibited is known as “lepto pose,” and is often an indication the sea lion is suffering the effects of the disease. (The Marine Mammal Center)

All told, about 70 percent of the sea lions the team tried to save have died.

Leptospirosis outbreaks among sea lions occur at fairly regular intervals, but changing ocean conditions—warmer waters and relocating fish—are affecting how the disease strikes populations along the Pacific Coast. The threats aren’t new, but they’re threatening in slightly new ways. Changes in marine conditions appear to be affecting the population’s resiliency to this disease and others. While researchers scramble to save sick sea lions today, they are also studying what this year’s outbreak can tell us about how sea lions will fare down the line.

The good news is that sea lions are fairly mobile and resilient animals. And until recently, their populations were booming. The National Oceanic and Atmospheric Administration announced in January that California sea lions had reached carrying capacity—the number of individuals their environment can sustainably support—in 2008.

Since then, though, their numbers have fluctuated. A “blob” of unusually warm and long-lasting water moved in along the West Coast from 2013 to 2015, causing widespread algal blooms that spread a neurotoxin called domoic acid throughout the marine food chain. Sea lions with elevated levels of the toxin suffered brain damage, resulting in strokes and an impaired ability to navigate, ultimately killing most of the afflicted individuals.

The warm water also sent fish and smaller marine life out to search for cooler environments, meaning the sea lions had to travel farther to find food. The combination of more distant hunting and impaired navigation led to record numbers of stranded pups—many taken in by the Marine Mammal Center—as well as a dip in the sea lion population during those years.

California sea lion Yakshack is one of 220 patients at The Marine Mammal Center in Sausalito, CA, that has been rescued so far this year impacted by a bacterial disease known as leptospirosis. The Center has been at the forefront of research on leptospirosis in marine mammals and has published a number of scientific papers on the disease dating back to 1985. (Bill Hunnewell / The Marine Mammal Center)

But the warm water conditions also led, ironically, to a decline in cases of leptospirosis during that time. Over the past decade, scientists have determined that the disease, which spreads via a parasite, is endemic to the population. Some animals carry the disease and don’t get sick, but they do excrete the parasites in their urine, which is how it spreads to other individuals. When sea lions haul out on a pier or beach, they freely roll around in each other’s pee.

When the blob of warm water appeared, sea lions had to swim farther to find food and had less time to haul out and be social, Johnson says, meaning less time sitting around in each other’s pee and parasites—and fewer cases of leptospirosis. But the lack of the disease a few years ago led to consequences today. Sea lions that get leptospirosis and survive develop antibodies that fend off the parasite in the future, says Katie Prager, a veterinarian researcher at UCLA’s Lloyd-Smith Laboratory who collaborates with the Marine Mammal Center. These antibodies, however, cannot be inherited by offspring.

“It’s not something that can be passed on,” Prager says. “Antibodies are something that the pup has to develop on its own.”

The warm waters meant fewer sick sea lions, but it left the population very vulnerable. Now the disease is back with a vengeance.

“A lot of the animals are now naive to that bacteria and their immune systems haven’t been exposed to that,” says Alissa Deming, a veterinarian researcher at Dauphin Island Sea Lab in Alabama who previously studied sea lion diseases at the Marine Mammal Research Center. “There is a group of animals that haven’t seen this before.”

The risk, according to the researchers, is that continued domoic acid outbreaks could result in a vicious cycle—fewer cases of leptospirosis produce unexposed populations, and then major outbreaks flare up like we are seeing this year.

“This is a great example of how environmental change has so much impact on a wild species—all the way from where they eat, where they migrate and how their diseases change over time, just based on a few degrees’ increase,” Johnson says.

California sea lion Herbie lays on his pen floor during treatment for leptospirosis at The Marine Mammal Center in Sausalito, CA. Veterinarians can usually identify leptospirosis in a patient even before laboratory tests confirm a diagnosis because of the infection’s distinctive symptoms in California sea lions, which include drinking water and folding the flippers over the abdomen. (Bill Hunnewell / The Marine Mammal Center)

The first documented case of a marine mammal suffering from the domoic acid toxin was in 1998, and the events are now increasing in frequency—so much so that the spread of domoic acid has become a yearly sign of the changing seasons around San Francisco Bay. “The days are getting shorter, pumpkin spice lattes are here and once again, it’s time for that other Bay Area rite of fall: worrying about the levels of toxins in local Dungeness crabs,” begins a recent San Francisco Chronicle article on the influence of the toxin on the start of crabbing season.

Sea lions don’t wait for permission from the Department of Public Health before they start eating crabs, though.

To exacerbate the issue even more, an El Nino event is predicted over the coming months, meaning warmer ocean waters off the West Coast and possibly more algal blooms and toxins. Already, Southern California waters—where researchers have found some of the highest concentrations of diatoms that produce domoic acid—have had record high temperatures this year.

NOAA has even deemed the recent warm-water years a “climate change stress test” for West Coast oceans. The agency said the conditions “may offer previews of anthropogenic climate change impacts projected for the latter part of the 21st century.”

If this has been a test, sea lions might not have passed, says Robert DeLong, a scientist with NOAA’s Alaska Fisheries Science Center. DeLong has been studying California sea lions for decades at their breeding grounds, Channel Islands off Santa Barbara. He says the species should be pretty resilient in the face of climate change, but the rate of warming waters is proving a major challenge.

Volunteers from The Marine Mammal Center in Sausalito, CA, release California sea lions Bogo (left), Brielle (center), and Biggie (right) back to the wild near Bodega Bay. All three sea lions were treated for leptospirosis at the Center’s Sausalito hospital. Many different animal species, including humans and dogs, can become infected with Leptospira through contact with contaminated urine, water or soil. The Center has a number of safety protocols in place to prevent transmission to veterinarians and volunteers working with sea lion patients. (Bill Hunnewell / The Marine Mammal Center)

The center of the West Coast sea lion population is around Baja California, so the species has adapted to warmer water than is currently being seen farther north up the coast. “They have that capability to live in warmer water,” DeLong says. And unlike, say, coral reefs, sea lions are very mobile, able to swim long distances to find suitable habitats.

But while males can chase food far up north, during the breeding season females are tied to a small radius around the rookery. If there is less food available there because fish have moved to cooler waters, it could present a major problem for sea lion mothers and their pups.

“So if this is what climate change looks like, and this period is an adequate proxy, if that’s really the case, then sea lions may not do as well as we would think,” DeLong says.

There are still signs of hope. Sea lions are increasingly moving north to new breeding grounds off the San Francisco Bay, for instance. The limiting factor is time.

“If the environmental changes are slow enough to adapt, they’ll be able to move and will probably move farther up the coast,” Johnson said. “If changes are slow enough, I could see them being able to adapt.”

The severity of carbonate chemistry changes from ocean acidification is predicted to increase greatly in the coming decades, with serious consequences for marine species-­ especially those reliant on calcium carbonate for structure and function (Fabry et al. 2008). The Northern California Current Ecosystem off the coast of US West Coast experiences seasonal variations in upwelling and downwelling patterns creating natural episodes of hypoxia and calcite/aragonite undersaturation, exacerbating global trends of increasing ocean acidification and hypoxia (OAH) (Chan et al. 2008) (Gruber et al. 2012). The goal of these experiments was to identify thresholds of tolerance and attempt to quantify a point at which variance in responses to stress collapses. This study focuses on two species: Cancer magister (Dungeness crab) and Haliotis rufescens (red abalone). These species were selected for this study based on their economic and ecological value, as well as their taxonomic differences. Respirometry was used as a proxy for metabolic activity at four different scenarios mimicking preindustrial, upwelling, contemporary upwelling, and distant future conditions by manipulating dissolved oxygen and inorganic carbon (DIC) concentrations. Both species showed a decrease in mean respiration rate as OAH stressors increase, including an effect in contemporary upwelling conditions. These results suggest that current exposure to ocean acidification (OA) and hypoxia do not confer resilience to these stressors for either taxa. In teasing apart the effects of OAH as multiple stressors, it was found that Dungeness crab response was more strongly driven by concentration of dissolved oxygen, while red abalone data suggested a strong interactive effect between OA and hypoxia. Not only did these two different taxa exhibit different responses to a multiple stressors, but the fact that the Dungeness crab were secondarily impacted by acidification could suggest that current management concerns may need to be focus more strongly on deoxygenation.

The ocean floor as we know it is dissolving rapidly as a result of human activity.

Normally the deep sea bottom is a chalky white. It’s composed, to a large extent, of the mineral calcite (CaCO3) formed from the skeletons and shells of many planktonic organisms and corals. The seafloor plays a crucial role in controlling the degree of ocean acidification. The dissolution of calcite neutralizes the acidity of the CO2, and in the process prevents seawater from becoming too acidic. But these days, at least in certain hotspots such as the Northern Atlantic and the southern Oceans, the ocean’s chalky bed is becoming more of a murky brown. As a result of human activities the level of CO2 in the water is so high, and the water is so acidic, that the calcite is simply being dissolved.

The McGill-led research team who published their results this week in a study in PNAS believe that what they are seeing today is only a foretaste of the way that the ocean floor will most likely be affected in future.

Long-lasting repercussions

“Because it takes decades or even centuries for CO2 to drop down to the bottom of the ocean, almost all the CO2 created through human activity is still at the surface. But in the future, it will invade the deep-ocean, spread above the ocean floor and cause even more calcite particles at the seafloor to dissolve,” says lead author Olivier Sulpis who is working on his PhD in McGill’s Dept. of Earth and Planetary Sciences. “The rate at which CO2 is currently being emitted into the atmosphere is exceptionally high in Earth’s history, faster than at any period since at least the extinction of the dinosaurs. And at a much faster rate than the natural mechanisms in the ocean can deal with, so it raises worries about the levels of ocean acidification in future.”

In future work, the researchers plan to look at how this deep ocean bed dissolution is likely to evolve over the coming centuries, under various potential future CO2 emission scenarios. They believe that it is critical for scientists and policy makers to develop accurate estimates of how marine ecosystems will be affected, over the long-term, by acidification caused by humans.

How the work was done

Because it is difficult and expensive to obtain measurements in the deep-sea, the researchers created a set of seafloor-like microenvironments in the laboratory, reproducing abyssal bottom currents, seawater temperature and chemistry as well as sediment compositions. These experiments helped them to understand what controls the dissolution of calcite in marine sediments and allowed them to quantify precisely its dissolution rate as a function of various environmental variables. By comparing pre-industrial and modern seafloor dissolution rates, they were able to extract the anthropogenic fraction of the total dissolution rates.

The speed estimates for ocean-bottom currents came from a high-resolution ocean model developed by University of Michigan physical oceanographer Brian Arbic and a former postdoctoral fellow in his laboratory, David Trossman, who is now a research associate at the University of Texas-Austin.

“When David and I developed these simulations, applications to the dissolution of geological material at the bottom of the oceans were far from our minds. It just goes to show you that scientific research can sometimes take unexpected detours and pay unexpected dividends,” said Arbic, an associate professor in the University of Michigan Department of Earth and Environmental Sciences.

Trossman adds: “Just as climate change isn’t just about polar bears, ocean acidification isn’t just about coral reefs. Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth’s climate history.”

“This study shows that human activities are dissolving the geological record at the bottom of the ocean,” says Arbic. “This is important because the geological record provides evidence for natural and anthropogenic changes.”

The findings mean the world might have less time to curb carbon emissions.

The world’s oceans have been soaking up far more excess heat in recent decades than scientists realized, suggesting that Earth could be set to warm even faster than predicted in the years ahead, according to new research published Wednesday.

Over the past quarter-century, Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought, said Laure Resplandy, a geoscientist at Princeton University who led the startling study published Wednesday in the journal Nature. The difference represents an enormous amount of additional energy, originating from the sun and trapped by Earth’s atmosphere — the yearly amount representing more than eight times the world’s annual energy consumption.

In the scientific realm, the new findings help resolve long-running doubts about the rate of the warming of the oceans before 2007, when reliable measurements from devices called “Argo floats” were put to use worldwide. Before that, differing types of temperature records — and an overall lack of them — contributed to murkiness about how quickly the oceans were heating up.

The higher-than-expected amount of heat in the oceans means more heat is being retained within Earth’s climate system each year, rather than escaping into space. In essence, more heat in the oceans signals that global warming is more advanced than scientists thought.

“We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the amount of CO2 that we emitted,” said Resplandy, who published the work with experts from the Scripps Institution of Oceanography and several other institutions in the United States, China, France and Germany. “But we were wrong. The planet warmed more than we thought. It was hidden from us just because we didn’t sample it right. But it was there. It was in the ocean already.”

The United Nations panel on climate issued a report warning of unprecedented temperature rise between 2030 and 2052 if global warming continues.(Reuters)

Wednesday’s study also could have important policy implications. If ocean temperatures are rising more rapidly than previously calculated, that could leave nations even less time to dramatically cut the world’s emissions of carbon dioxide, in the hope of limiting global warming to the ambitious goal of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels by the end of this century.

The world already has warmed one degree Celsius (1.8 degrees Fahrenheit) since the late 19th century. Scientists backed by the United Nations reported this month that with warming projected to steadily increase, the world faces a daunting challenge in trying to limit that warming to only another half-degree Celsius. The group found that it would take “unprecedented” action by leaders across the globe over the coming decade to even have a shot at that goal.

Meanwhile, the Trump administration has continued to roll back regulations aimed at reducing carbon emissions from vehicles, coal plants and other sources and has said it intends to withdraw from the Paris climate accord. In one instance, the administration relied on an assumption that the planet will warm a disastrous seven degrees Fahrenheit, or about four degrees Celsius, by the end of the century in arguing that a proposal to ease vehicle fuel-efficiency standards would have only minor climate impacts.

The new research underscores the potential consequences of global inaction. Rapidly warming oceans mean that seas will rise faster and that more heat will be delivered to critical locations that already are facing the effects of a warming climate, such as coral reefs in the tropics and the ice sheets of Greenland and Antarctica.

“In case the larger estimate of ocean heat uptake turns out to be true, adaptation to — and mitigation of — our changing climate would become more urgent,” said Pieter Tans, who is the leader of the Carbon Cycle Greenhouse Gases Group at the National Oceanic and Atmospheric Administration and was not involved in the study.

The oceans absorb more than 90 percent of the excess energy trapped within the world’s atmosphere.

The new research does not measure the ocean’s temperature directly. Rather, it measures the volume of gases, specifically oxygen and carbon dioxide, that have escaped the ocean in recent decades and headed into the atmosphere as it heats up. The method offered scientists a reliable indicator of ocean temperature change because it reflects a fundamental behavior of a liquid when heated.

“When the ocean warms, it loses some gas to the atmosphere,” Resplandy said. “That’s an analogy that I make all the time: If you leave your Coke in the sun, it will lose the gas.”

This approach allowed researchers to recheck the contested history of ocean temperatures in a different and novel way. In doing so, they came up with a higher number for how much warming the oceans have experienced over time.

“I feel like this is a triumph of Earth-system science. That we could get confirmation from atmospheric gases of ocean heat content is extraordinary,” said Joellen Russell, a professor and oceanographer at the University of Arizona. “You’ve got the A team here on this paper.”

But Russell said the findings are hardly as uplifting.

The report “does have implications for climate sensitivity, meaning, how warm does a certain amount of CO2 make us?” Russell said, adding that the world could have a smaller “carbon budget” than once thought. That budget refers to the amount of carbon dioxide humans can emit while still being able to keep warming below dangerous levels.

The scientists calculated that because of the increased heat already stored in the ocean, the maximum emissions that the world can produce while still avoiding a warming of two degrees Celsius (3.6 Fahrenheit) would have to be reduced by 25 percent. That represents a very significant shrinkage of an already very narrow carbon “budget.”

The U.N. panel of climate scientists said recently that global carbon emissions must be cut in half by 2030 if the world hopes to remain beneath 1.5 Celsius of warming. But Resplandy said that the evidence of faster-warming oceans “shifts the probability, making it harder to stay below the 1.5-degree temperature target.”

Understanding what is happening with Earth’s oceans is critical, because they, far more than the atmosphere, are the mirror of ongoing climate change.

According to a major climate report released last year by the U.S. government, the world’s oceans have absorbed about 93 percent of the excess heat caused by greenhouse gases since the mid-20th century. Scientists have found that ocean heat has increased at all depths since the 1960s, while surface waters also have warmed. The federal climate report projected a global increase in average sea surface temperatures of as much as nearly five degrees Fahrenheit by 2100 if emissions continue unabated, with even higher levels of warming in some U.S. coastal regions.

The world’s oceans also absorb more than a quarter of the carbon dioxide emitted annually from human activities — an effect making them more acidic and threatening fragile ecosystems, federal researchers say. “The rate of acidification is unparalleled in at least the past 66 million years,” the government climate report stated.

Paul Durack, a research scientist at the Lawrence Livermore National Laboratory in California, said Wednesday’s study offers “a really interesting new insight” and is “quite alarming.”

The warming found in the study is “more than twice the rates of long-term warming estimates from the 1960s and ’70s to the present,” Durack said, adding that if these rates are validated by further studies, “it means the rate of warming and the sensitivity of the Earth’s system to greenhouse gases is at the upper end.” He said that if scientists have underestimated the amount of heat taken up by the oceans, “it will mean we need to go back to the drawing board” on the aggressiveness of mitigation actions the world needs to take promptly to limit future warming.

Beyond the long-term implications of warmer oceans, Russell added that in the short term, even small changes in ocean temperatures can affect weather in specific places. For instance, scientists have said warmer oceans off the coast of New England have contributed to more-intense winter storms.

“We’re only just now discovering how important ocean warming is to our daily lives, to our daily weather,” she said.